title: Homocystinuria: studies on cystathionine beta-synthase, S-adenosylmethionine synthetase and cystathionase activities in skin fibroblasts.
abstract: Cystathionine beta-synthase, S-adenosylmethionine synthetase and cystathionase activities were assayed in skin fibroblast cultures from five pyridoxine responsive and five pyridoxine non-responsive homocystinurics, six obligate heterozygotes for homocystinuria and ten normal control subjects. The specific deficiency in cystathionine beta-synthase activity was confirmed in nine of the homocystinuric cultures. However, in one pyridoxine responsive case the level of cystathionine beta-synthase activity was found to be comparable with those of the heterozygotes. A negative correlation appeared to exist between the level of residual enzyme activity and the pre-treatment severity of clinical symptoms.
mesh_terms: D002478:Cells, Cultured; D003541:Cystathionine beta-Synthase / Q000378:metabolism*; D003542:Cystathionine gamma-Lyase / Q000378:metabolism*; D005347:Fibroblasts / Q000187:drug effects / Q000201:enzymology; D006580:Genetic Carrier Screening; D006712:Homocystinuria / Q000201:enzymology*; D006720:Homozygote; D006801:Humans; D006836:Hydro-Lyases / Q000378:metabolism*; D008190:Lyases / Q000378:metabolism*; D008716:Methionine Adenosyltransferase / Q000378:metabolism*; D011736:Pyridoxine / Q000494:pharmacology; D012016:Reference Values; D012867:Skin / Q000201:enzymology*; D014166:Transferases / Q000378:metabolism*
chemical_list: D014166:Transferases; D008716:Methionine Adenosyltransferase; D008190:Lyases; D006836:Hydro-Lyases; D003541:Cystathionine beta-Synthase; D003542:Cystathionine gamma-Lyase; D011736:Pyridoxine